When to plant radishes in Indiana
Indiana’s average last spring frost is April 24, and the first fall frost typically arrives around October 11 — about 170 frost-free days (USDA zones 5b, 6a, 6b). Radish needs 22–30 days to mature, which fits comfortably within Indiana's growing season.
When to plant radishes in Indiana: the short answer
For a spring planting, sow Mar 22 – Apr 10. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Indiana: Apr 6 · Apr 16 · Apr 26 · May 6 · May 16 · May 26
Spring succession stops before summer heat makes it bolt. Start sowing again in late summer for a fall crop (see the fall window above).
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow radishes in Indiana, step by step
- Prepare the bed. They need six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 6 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Sow outdoors (Mar 22 – Apr 10). Space plants about 2 inches apart in rows 6 inches apart, sowing seed ½ inch deep. It handles frost well, so it can go out before the last frost date. As a cool-season crop it does best before summer heat arrives in Indiana.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: flea beetle, cabbage root maggot, aphids. Diseases and disorders: clubroot, scab, downy mildew.
- Harvest (from about Apr 18 – Apr 26). Radish takes 22-30 days to reach harvest. The classic marker crop and quick filler. Sow a short row every 10 days - a single big sowing all matures at once and then goes pithy and hot.
Figures come from our crop data; dates use Indiana’s average frost dates. More in the full radish growing guide.
Radish planting dates by USDA zone in Indiana
Indiana spans USDA zones 5b, 6a, 6b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the radish dates shift with them.
When to plant radishes in nearby states
Questions gardeners in Indiana ask
When is the best time to plant radishes in Indiana?
Sow radishes in Indiana between March 22 and April 10. That timing is set by Indiana's average last spring frost of April 24.
Can I plant radishes in the fall in Indiana?
Yes. For a fall crop, sow between August 27 and September 13, so the crop matures in cool weather before Indiana's first frost around October 11.
When will radishes planted in Indiana be ready to harvest?
Planted on time, radishes are usually ready from about April 18 to April 26, 22-30 days after sowing.
When is the last frost in Indiana?
On average around April 24, with the first fall frost around October 11 - about 170 frost-free days. Your town may differ by two weeks or more.